First Test Flights: Unexpected Results
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- Опубликовано: 28 май 2024
- Last time I flew my airplane was December 15, 2023. I expected to do maintenance for two months and be flying again by the end of February. Four months later, I have finally finished all of the repairs and modifications, and it's time to start the test flying phase. I have written up a set of test cards for testing individual systems in a gradual way.
In this video I go through the final preparations, first test flights, more fixes, and another, third test flight - and the results.
0:00 Intro
1:12 Run-Up Test
4:22 Run-Up Results
5:08 Re-Cowl
5:42 First Two Test Flights
8:23 Flooded Fields
8:40 Post-Flight
9:26 Problems Discovered
16:20 Building Diffuser
21:51 Baffle Problems
23:32 New Diffuser
24:51 Broken Bracket
29:15 Sealing Baffles
29:55 Installing Diffuser
31:18 Re-Cowl
31:49 Pre-Flight
32:14 Third Test Flight
34:14 Cylinder Head Temperatures
37:58 Cruise Temperatures
39:16 Cedar Point Amusement Park
41:06 Approach and Landing
#Canard #Cozy #Airplane 
Авто/Мото
Great video. With high CHTs, especially after maintenance, double check your ignition timing. Good idea getting the baffling buttoned up as well.
I thought that, but the problem exists even if I select just the mag or the electronic ignition, and the chances of the timing going bad on both at the same time is pretty remote.
@@CanardBoulevardYes I agree
Agree. It only takes a few degrees of advanced timing n to run the CHTs high. You can also check your engine data...you will see higher CHTs and lower EGTs with advanced timing.
Scott, You truly are a Perfectionist. You leave nothing to chance.
It is kind of a requirement in aviation.
Biggest impacts to cooling are timing and mixture not (within reason) airflow.
Since the fuel nozzles bleed to outside air pressure, increasing air pressure at the bleed makes a leaner & hotter cylinder
Glad you are back in the air. You have worked very hard on your airplane!
Thanks for this video, Scott. Nice to see you're flying again.
Thanks for the content, Scott... I very much enjoy watching your channel. I have wanted to own and fly a Long EZ since I was a kid. I got my private.. single engine land in th lat 80's, but only have time in Cessna 150, 152, and 172 aircraft. I never got too fly in any pusher aircraft at all... I am living vicariously through watching you fly the Cozy!!! Thanks again!
A really informative aviation video. Nice work!
black spots on prop are likely exhaust condensation... same you see coming out a car tailpipe
Is the new prop dissimilar in pitch and size than the previous one? Different loading, thus thrust and rpm may be causing the temp to rise higher than previous. One simple test would be to put the original prop back on an try that? Johnston's baby oil may also help get the prop clean - it works with car exhausts :)
The distribution of thrust on this prop is different, but it is the same diameter as the old one, but yes, that is definitely a consideration.
All great stuff ! Seems like one can of worms just leads to another lol doing a great job sorting it out ! Thanks for the content 👍
@CanardBoulevard >>> Great video...👍
Nice job! On the cowling!
Maybe the new prop is causing the cylinder temp issue?
Great video!
Make sure the hot air can get out
A very exciting episode. May Elias be always with you!
Nice job on the go around!
I have no problem going around if things don't look right. :)
NACA duct, good idea. I had a 1" inlet, 3" long side and blew a ton of air. Do you have somewhere for the cabin air to get out? Stainless clamp, safety wire it? We have small loops welded to the exhaust pipes that have a stranded stainless wire attached to the engine. If the pipe breaks off it can't get to the prop. I'll be following your CHT saga as mine are doing the same thing on a Velocity and I've tried everything to fix it! I wonder if another plate on your diffuser could direct the airflow at the cys?
You're thinking there isn't enough cabin air outflow for the heated air to flow in? That's what I'm thinking.
The engine is going to end up with 4 electric fans each controlled according to its own temperature measurement!
I've been really enjoying your vids! Simply LOVE the Cozy and Long EZ's. Keep doing what you love for as long as you can and God Bless my friend!
Theory on your cooling: if I remember from your previous videos your cabin heat dumps (What could be cooling) air into the low pressure side of your baffling when in the off position and thus reducing the differential pressure below and above your cylinders. Consider sealing that off to collect data. I bet your cabin heat and cooling issues are intertwined.
As I remember it, the cabin air heat exchanger needs air to always pass through it. Otherwise the heat exchanger will get too hot for the material it's made from.
So I guess the pipe that takes _unwanted_ heated air to the low pressure side of the cowel can't be blocked off, even for a quick circuit.
On another issue, I'm thinking the poor hot air flow into the cabin is perhaps a lack of an air exit path from the cockpit.
doesn't the glare coming off the top of your instrument panel bother you? glare panels are usually black...
It's seen by the camera, but not by the pilot inside. I would make it black, but it is directly over the expensive avionics, and I would rather not cook the avionics with heat.
I noticed something pertaining to your fox on the prop. When you were talking about the screw clamp being missing I noticed black what looked like exhaust on the bottom of the pipe that the clamp came from. It looks like spatter from the engine. Carbon or oil from maybe an issue with a cylinder. You may want to check that !!!! Better safe then an oh shit moment! Just saying
That's from when the oil breather outlet used to be on that side of the engine. I moved it to the other side now.
Oh yeah, finally lovin the test flight, get the cylinders to cool down a bit, maybe some disappointment, but you'll figure it out.
Lol, I said "nice" when you landed and then a second later you said it the same way.
Put the old prop
Back on and check CHT’s
Engine working harder to turn that new prop, compare previous speed to rpm, ?
A safety wire on the hose clamp would be a good idea.
A couple of observations if I may? Firstly if you want something air cooled cool, supply air directly to it. Secondly, imagine that cowl contents on the outside of your aircraft. Would that arrangement provide acceptable airflow outside the aircraft? If not you might want to ask why putting it inside a cowling would make any difference? The air paths inside that cowl are chaotic and indirect, to say the least.
Awab brand hose clamps are much better clamps. They are used in the marine industry. They cost a bit more but worth every penny.
I power my cameras from a standalone power pack. I have found it to be a game changer. I found the GoPro to be sensitive to low amps (not surprisingly). I chose a power pack, problem solved. I can also get the cameras going early (before aircraft power on) and just forget about it.
Regarding the high CHTs, is there a way you can check that the indicated temperatures are correct?
TIL "grazing mode"
alternate title: "a series of baffling problems"
Remove the blast heat. Check intake leaks. Verify mechanical engine timing then ignition timing. Verify oil cooler and varistat. Did I see a zip tie on an intake tube? Your very calm👈🐱👍
I already pulled the blast tube from the heater shroud - no difference (except that the heat works just fine using the pressurized air from under the cowl, without the blast tube). I will be doing timing checks very shortly, oil cooler and variostat are good. You might have seen a GripLockTie on an intake tube to help hold it up out of the way of airflow.
Did you figure out what the cooling problem is? Obviously not enough air, either restrictions on the inlet or outlet.
You need to safety wire those clamps because they will loosen up.
I may be wrong, but the clamps on the exhaust look like regular hose clamps, not sure if they are rated for high temperatures. Normal high temp exhaust clamps are a T bolt style. Just a thought. Fly safe!!
They are stainless, just like the exhaust pipes themselves.
I would put some type of safety wire on those hose clamps on your exhaust, just a suggestion?
Great progress great vid, Why do people Vocal Fry on VHF?
Yeah, they think it sounds cool or something. Drives me crazy.
There is a NACA/ NASA document, available from Cranfield Repository, indicating NACA Air Intakes are not the best.
Blessings +
You definitely had two blast of white smoke on startup.
Could that have caused the splatter on the prop?
Good looking aircraft
Check mixture cable? maybe running leaner than indicated?
I would know if that were the case because the EGTs would be off.
Could you switch to U-bolt style muffler clamps to replace the flimsy radiator screw clamps that can't take the heat/expansion of your exhaust pipes? Might save a prop.
Too heavy, and would damage the thin, delicate (and very expensive) stainless titanium alloy pipes. Those screw clamps are special stainless designed for this type of thing - I'm not sure why the one failed, as I never found it.
Thinking about your cooling issue. The blades on the new prop have little airfoil near the hub. May not produce enough suction power to cool.
It's possible. I'm actually talking with the prop manufacturer about this right now.
Did you read: 'Des couacs chez les canards'?
-Kwaks among ducks
There is an english translation in the site 'Homebuilt Aircraft and kitplanes'
Blessings +
First time viewer. Is it possible to fly the old prop agan? Those temperatures are not too hot.
It's in the plans, yes.
I have an idea Scott. Could you take a reversible shop vac.... And fabricating adapter to fit over the lower air intake where your diffuser is and in the hangar turn it on and have it blow air into the diffuser and go around to the engine compartment and see how the air is behaving as it blows up through the engine compartment? I figured that might be a way to view the aerodynamic behavior of the airflow without possibly having to fly the airplane who knows?.... Maybe it might reveal something. Just an idea
One better, I have a high-volume blower that I'm going to use to do this.
After the work you've done along with the new air scoop, I can't help but feel that the exit pressure from the engine must be too high causing air stagnation. Is the exit area from the cowling greater than the air intake area?
I don't think so, but I'm going to be doing a differential pressure test just to be sure in any case.
Not being able to see from here but wondering if there is any mounting between the two exhaust pipes. Heat & vibration would allow the distance between them to change and allow the clamp to loosen if there is no attachment to each other nearby. Also, I always avoid using worm clamps whenever possible because of their tendency to come loose, especially when not clamping something that has no resiliency (rubber, silicone, etc.) Also - temperature readings will change with supply voltage changes. Possibly your recent repairs to the electrical system created a change to your readings. I'd do a back-up / proof test by placing a sensor in a cup of heated water alongside a trusted mechanical thermometer. Maybe there is an adjustment/correction ability built-in to the system?
The worm clamps have been holding those exhaust pipes in place for >20 years now. I'm not sure what caused this one to decide that today was the day, but I've resolved the issue now anyway - if one comes off again, it will not be going through the prop.
The temperature sensors are K-type thermocouples - they actually generate voltage depending on the temperature, so they are completely independent of, and unaffected by supply voltage.
What a cool airplane, Nice video :) I am new to this with airplanes and aircraft. i will start my ppl training this fall. But one thing I have noticed when I look around here on youtube and all the flight videos is that the finish on the construction in the engine compartment looks like it would be built in kindergarten. cables hoses hanging here and there. crooked and twisted. Everything looks so amateurish. Junk buildings. even on factory-built pipes or cessnas, the same junk building. Do you not have greater requirements in aviation. This is what you have to get used to. Not that it scares me but I just wonder if it is this standard overall on small airplanes. :) Happy flying to all. see u in the air later on hopefully if i get my ppl :)
What you see is the results of 20 years of upgrades and changes. You could rip out everything, start over, and make it look nice and neat, but it's still going to work just the same.
Hard to get it up when the OAT is 46
The best way to to increase engine cooling is NOT to worry so much about the intake section, BUT look into the exit and make it an EXTRACTION rather than a FLOW. PULLING air is far more effective than FORCING air. Forcing air creates abnormal chamber pressures. Extracting air creates a LOW PRESSURE system and reduces the air temperature while it works. One way to do this is with a modified exhaust system that helps drive the air our of the engine compartment. Work on that.
I'm going to be testing for this shortly, doing a pressure delta test across the engine.
Yo, that hose clamp that went through the prop. I’m sure there’s a ton of heat on the exhaust pipe, especially right near that bend, if the clamp was very tight I can imagine it getting super hot and just letting go I suppose. I wonder if there are hose clamps specifically made for high heat scenarios.
If your cylinder head temperatures (CHT) are too high on those two cylinders, why do you continue to fly? Is it high, just not alarmingly high? Not trolling you, I really don't know and am curious. Thanks!
They are elevated during climb - I can mitigate it by pulling the power back after initial climb, and they are OK during cruise - not ideal, but definitely within a safe envelope. If they were high enough to cause damage, I would not be flying with it.
@@CanardBoulevard Thank you for taking the time to answer that question. I have been a fan of Canards for a long time, and appreciate your channel. Thanks again.
I would have someone while you do a 70% run-up for about 2mins, use a IR temperature reader, and confirm you gauge readings.
It possible its NOT a correct reading, and the gauge needs to be calibrated.
The CHT's are K-type thermocouples, and they are all independent. The chances of all four of them going bad at once is pretty remote.
I thought in the previous video, it was said if the heat isn’t going into the cabin, then it’s being dumped on the engine….. could be the cause of the engine temp issues.
No, that is a very small amount of heat, and it gets dumped overboard, nowhere near the cylinder heads.
You might want to re-think the use of hose clamps in critical applications . With the vibrations generated by most aviation engines who are literally trying to shake them selves apart . No Mater what the band is made of they are not the proper way to clamp something of importance. Why is the exhaust stack so loose?
That is how these planes are built, and those clamps have been on this airplane exactly like this for 20 years. The exhaust headers are independent, each one goes to a slip joint on the header flange, so they need to be held together to AVOID vibration. They aren't CRITICAL, but without them you could end up with vibration-induced wear.
Are you allowed to fly with the engine cowling off?
Allowed - yes. But this would be extremely bad, as the engine would overheat and be destroyed almost immediately. It depends on the airflow being ducted into and forced through the cylinder fins in order to cool the engine. Without the cowling in place, that does not happen.
I doubt you’ll get any benefit from a new duct unless it’s a straight ram, because the issue is pressure difference front to back. Work at sealing up the nose, foam blocks can go on the elevator opening. A boot over the nose gear actuator. Once you don’t have the same pitot pressure up front, the heater will cook you out of the airplane
I have foam blocks in the elevator openings already, as well as around the gear actuator. It's still leaky...I'm going to replace them with neoprene socks adhered to the elevator tubes and the fuselage side to fully seal it off.
How about temperature sending units or guages ? 👨✈️Also, is OIL temperature normal
Oil and EGTs are normal. It would be very unusual to have all four sending units go bad at the same time, and the gauge is a digital G3X EIS, so not something that goes out of calibration.
Do the four individual temp sending units feed to one digital unit or signal generator of some sort? Good luck😎
Have you swapped the sending units from the two cylinders, and see what occurs under the same test conditions? I don’t know a lot about recips, having said that, a friend is chasing a similar issue on his Harmon Rocket. He also, is making cowl mods. Nothing has improved yet? I always think electrical 😎
Auto Body clay to get those spots off prop
Good idea. I'll give that a try.
What field you flying from?
1G5 Medina
- Cool. Some more debugging, but it seems to be flying pretty well. Smooth landing at the end.
Verry nice flight after all the work you did.
Does your plane have the bottom air brake flap?
I didn't hear you deploy it.
Thanks and I love following your journey....
Yes, you can see him test deploy it in the engine test early in the vid.
Yes it does. I had extended it before the landing you see here, but it was definitely out.
from outside the velocity-canard - pusher seam to be the best plane concept and save because of his stol caracteristic...why this concept is the only one...so many new aircrafts on the market, now one builds this ruton concept ???
Yo scott do you get nervous doing a test flight after a long break and maintenance like this? Whats the feeling like going down the runway after making all these repairs and getting the plane back up in the sky after months?
Can't speak for Scott, but you have to be very confident that you have done everything needed for safe operation of the aircraft. At a certain point, you just need to buck up and go.
I spend a LOT of time making sure everything is perfect first. That's why I started with a ground run, inspection, then single pattern, inspection, before leaving the airport area.
Wow - that high pitch when you play at fast speed is kinda miserable. If you need help editing let me know.
Oh man, I usually mute that part of the video when I speed it up, I totally missed it. Sorry about that.
Not a problem! I typically listen to flying videos when I’m falling asleep so the high-pitched noise woke me up :-)
I didn't see it fly
Or have somebody fabricate a cowling made of heavy duty screen material
Is that 15 seconds plus of cranking the starter to start normal?
Is best practice to never allow an engine to not be run up to operating temp for more than a week if possible? That's a general rule of thumb in terms of automotive 4 cycle gas or diesel engines.
Does a 3 blade prop's 50%ish more resistance make more work for the engine?
I was very nervous after that 15+sec cranking to start. But I'm completely unfamiliar with piston aviation.
Most aircraft engines sit for months between running. As do most boat engines! If you run an injected aircraft engine once a week then 2 seconds of cranking typically starts it. There is effectively no prop resistance at low rpm's.
The engine had not run in 4 months. Now that it is being run regularly again, it starts in a second or two.
Just a thought about cooling but may be some where some how the air can't leave quick enough for proper flow. Love the videos and thank you for them.
Wait is there a choke or something in there? You mentioned ‘leaning the mixture to not foul the plugs’.
no, it's a fuel injected aircraft engine. The throttle body regulates the fuel air mixture. We use a mixture control to lean out the engine as we fly higher.
Hi Scott,
Enjoy your videos. Were you provided the plans for your Cozy when you purchased it? It looks like you are missing some of the baffling on your lower cowl as per the plans although it's hard to see in the video. It also looks like as per the plans you are missing your interior cylinder baffles that butt up against the engine case. Might help with the cooling.
Is there a Cozy Owner’s Club that you belong to? These types of clubs are great for brainstorming with when faced with such problems as overheating cylinders and cabin heating issues.
What is your fuel flow?
Try WD40 to remove the prop splatters...
Nope. Tried it. Also MEK, anhydrous alcohol and several types of cleaners. Nothing touches it.
I can't wait to find out why the cylinders are so hot.
I think 2200 static rpm full throttle at your elevation is too low. That's probably 6 inches of MP over square. Is the 0 360 rated for that? I know 0 320s were good for about 5.
Weiman Ceramic and Glass Cooktop cleaner works good for cleaning props. 100LL would probably dissolve that stuff too.
A left field idea. Stevefranseen is probably correct. What if its 5 pounds of air with a 10 pound air requirement? Pop up top scoops on the top cowling? I don´t know I am not an aviation guy. You now have more air running to the heater, and another duct for your old hot cylinder. This is totally not taking into account, High pressure side, low pressure side, etc. But, the cylinders are on top. What if you treat bottom air as a thing, and top air as a thing. Then make that adjustable so you don´t run too cold in cold weather.
It may be totally no bueno. Basically your issue was the wife is cold and one hot cylinder. That may not fit at all, I don´t have a good idea of how the high pressure side, low pressure side works. But, Brute Force Cooling may work without disrupting what you have going on in the lower segment. Or, it may be impossible due to high side, low side? You tell me?
Plus you get algorithm up for comments.
I figured you might have high RPM alternator output magnetic issues with the wiring, Maybe... This is unexpected. But... Like I was saying. IDK, the scoops may draw from air for the prop to bite? Again, you tell me. Left field is to do course adjustment, as in course sand paper vice fine sandpaper. You seem to be stuck with fine adjustment. You may just need more airflow where you need it.
Also, maybe cowl flaps rearward facing on the top? Find an HVAC Person and have them look at it? They might just look and say "Well obviously its..." while punching buttons on their calculator. Maybe it exhaust side and not supply side?
If I could make one critique, you do chains of "This IS this. and This IS that." I recommend you do more "This MIGHT be this. Or this MAY be that." or you build a mental Jenga tower. Nothing is anything until its shown to be that. Not theory. You know where I am coming from on that. Again, I like how you do risk management on doing what is more or less "Green Field" stuff. Its advice, to be taken as such. You are the one strapping your backside in it and doing the final "Go, No Go" Gauge testing. This is just pass forward on that sort of development cycle in other fields.
What you fixed is what was making it work before? Now its too air tight? It was obviously in some sort of balance. Call an HVAC guy and barter a ride for an opinion. Plus its makes for good video etc.
The clamps,. x2 clams less tight, if its vibration breaking?
Hope its helpful, that's the idea.
Jamie out.
Isn't this the type of plane John Denver was killed in. Not for poor piloting skills but for poor placement of fuel tank switching lever.
ruclips.net/video/Q17uzUe0bAk/видео.html
Safety wire anyone?
Safety wire would not have helped that clamp from going through the prop, it still would have come off the exhaust and through. What I did do, where I moved it to, will prevent it in the future.
for the splatter, try olive oil to remove it (i know, but it may work)
Ty raps are cheap, use more on your engine wiring.
Tie wraps or "zip ties" as I call them would not be appropriate on an exhaust pipe assy. Plastic like that melts under really high temps ... what's ok for holding a wire bundle together inside the instrument panel, and cabin, is not ok in the high temp area of the engine bay.
@@user-fk5tt4tx5y So you just let them hang loose?
@michaelsamson3276 No, of course, Scott needs an appropriate clamp for the temperatures as has been suggested by others above. I was just saying that "zip ties" are not appropriate in this specific location. Perhaps something made out of titanium to handle the high temps. I don't know a specific part number off the top of my head, but the decision on what to use lies with Scott since it's his aircraft.
@@user-fk5tt4tx5y Actually the FAA guidelines are pretty clear. In areas the will be subjected to something like 450F, you need to use metal locknuts. Otherwise ty raps are just fine everywhere except within a couple of inches of the exhaust system All spark plug harnesses come with nylon ty raps for example. The only times they are damaged is when plug wires with ty raps on them rest on the cylinder head fins. High performance turbo engines cause ty raps to get brittle sooner if they are used in the exh system areas.
I actually use GripLockTies that Mike Patey created - they are high-strength, removeable, reusable zip ties that have a silicone surface on the inside that a) grip better, and b) won't cause wear or abrasion like standard nylon zip lock ties.
Seems like a disaster in progress...